Why does eczema sting?

Why does eczema sting?

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Written By Dr. Joshua Townley, BForensSc, PhD.

eczema sting

Eczema, also known as atopic dermatitis, is a common skin condition characterised by red, itchy, and inflamed skin patches. It is estimated that 15-20% of children and 1-3% of adults are affected by eczema1. While itch is the most well-known symptom of eczema, many patients also experience a stinging sensation. But why does eczema sting?

Pain and itch

Separating pain from itch

While the sensation of itch (known as pruritus) and stinging/pain are closely related, they are actually distinct processes2. An itch signal travels from the skin along special nerve cells called C-fibres up to the spinal cord, then on to the brain. The body’s natural reaction, scratching, essentially triggers a mild pain response that dislodges the itch signal3, and the brain dispenses some of the feel-good chemical serotonin as a reward4.

One study found that the majority (83.2%) of people with eczema found that their pain was caused, at least partly, by scratching5, which makes sense given what we know about the itch-scratch cycle6. However, there is also evidence that pain in eczema is not always associated with itch or scratching, and may involve a neuropathic component, or a malfunction of the nerves themselves, that is, so far, poorly understood7. Nevertheless, we do know that while scratching is often a factor on the surface level, there is more taking place behind the scenes.

Mechanisms

Mechanisms of eczema pain

The skin barrier

It’s clear that most people with eczema experience pain such as stinging as a result of their condition8, while up to 80% also describe themselves as having sensitive skin9. By comparison, the worldwide prevalence of sensitive skin in the general population is around 40%9. Research indicates that, at least to some degree, this increased pain and sensitivity is caused by a weakened skin barrier10. People with eczema were found to be more sensitive to electrical stimulation of sensory nerves compared to people with normal skin. However, when people with normal skin had their skin barrier damaged, either through tape-stripping to remove the outer skin layers, or by removing skin lipids with solvents, they too experienced increased sensitivity10. In the real world, a damaged skin barrier can mean irritants or allergens are more easily able to penetrate the skin and trigger an immune response, resulting in itch, inflammation and potentially pain.

Nerve fibre density

People with eczema also seem to have a higher density of nerve fibres in their skin, which might contribute to the heightened sensitivity to itch and pain11. While the reasons for this aren’t completely understood, it may be caused by chronic inflammation, which increases the production of certain nerve growth factors in the skin12.

The role of inflammation

Finally, inflammation itself, or the release of inflammatory mediators in the skin, contributes to pain and skin sensitisation8. Interleukin-33, one of these inflammatory mediators, has been shown to boost inflammation and pain, and is elevated in people with eczema13. Worse, scratching the skin triggers the release of more interleukin-33, kicking off the itch-scratch cycle, reducing skin barrier function and exacerbating the problem13.

Management

Managing eczema pain and stinging

The strategies to minimise stinging associated with eczema are very similar to those recommended for minimising itch.

  • Keep skin moisturised – The skin barrier must be hydrated to work effectively
  • Avoid common irritants – These include fragrances, lanolin, propylene glycol and soaps, as well as certain fabrics like wool
  • Use water-free, occlusive ointment – When skin is very dry and cracked, even water in a moisturiser formulation may cause stinging
  • Cold compress – A cold compress can temporarily relieve the stinging sensation
  • Corticosteroids or other anti-inflammatories – talk to your doctor about the most appropriate treatment to help manage inflammation
  • Pain relief – if these strategies aren’t enough, talk to your doctor about targeted pain relief

Eczema is a complex condition that can cause both itching and stinging, and for some people the pain is entirely separate from itch. Interactions between the skin barrier, nerve sensitisation, and inflammation all play a role, but there is still much we don’t know about the underlying causes and mechanisms. Managing eczema pain and stinging is key to improving overall quality of life, and a combination of barrier repair, avoidance of irritants, and targeted treatment can help provide relief. It is always important to consult with a healthcare professional for proper management and treatment of eczema.

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